Osteoporosis is a major worldwide public health problem with over 20 million individuals affected in the united states. Over 1.5 million fractures occur in the united states annually, resulting in 750,000 visits to the physician and long term hospitalization with a total impact to the health care system in excess of billion dollars. The current state-of-the-art in clinical diagnosis for Osteoporosis is bone density measurements which can be use neither to predict the onset of disease nor monitor the shot term effectiveness of therapy. At present, the only clinically useful diagnostic tolls for this purpose are microtitre plate immunoassays which are cumbersome to use and are available only in large clinical laboratories. Eyre and colleagues have identified and characterized the N- telopeptide cross-linking domain of type I collagen (NTx) as a highly specific marker for bone resorption. A microtitre plate immunoassay for this analyte has been commercialized by Ostex International, Inc., of Seattle, WA, and approved by the FDA. Metrika laboratories will develop the Digital Response NTx test which is a single-use, disposable, bone resorption assay based on the simultaneous measurement of the NTx bone specific marker and creatinine to yield a normalized quantitative result. The test device, which will be about the size of a credit card, will combine inexpensive microelectronics and dry reagent immunochemistry. This innovative test will be extremely simple to operate and will provide a digital display of results in a few minutes. The technology of Digital Response will benefit patients by providing a convenient and inexpensive method to monitor, at the point-of-care, the effectiveness of treatment to reduce accelerated bone loss in postmenopausal women.